Apparatus for coating under water

ABSTRACT

A method of applying a protective coating to a surface under water which comprises forcing a protective coating composition through an applicator pad, for example using compreseed air, at a pressure at least equal to the ambient pressure of the water at the depth at which the coating is applied, and applying the coating composition to the surface by a smearing action of the pad. Apparatus for carrying out the method includes a porous applicator pad, a reservoir for a protective coating composition to be supplied to the applicator pad, a sensing device for sensing the ambient water pressure, and a control device operative to maintain the pressure at which the composition is supplied to the applicator pad at least equal to the sensed pressure. The applicator pad may be a layer of foamed plastics material having an open interconnected cellular structure.

United States Patent [1 1 Jones Oct. 23, 1973 1 APPARATUS FOR COATINGUNDER WATER [76] lnventor: David Fitzherbert Jones, Plummet Water,Narley Woods, Lymington, England [22] Filed: Apr. 26, 1972 [21] App].No.: 247,704

Related US. Application Data I [62] Division of S er. No. 821,776, May5, 1969,

abandoned.

[52] US. Cl 114/222, 15/l.7, 118/7, 118/266, 401/204 [51] Int. Cl B631)59/00 [58] Field of Search 118/7, 9, 10, 266,

[56] v References Cited UNITED STATES PATENTS 2,007,603 7/1935 Green118/307 X 3,143,756 8/1964 Sisko.... .l. 401/188 3,159,499 12/1964 Jorda117/2 3,340,561 9/1967 Schwartzman.. 401/206 X 3,396,423 8/1968 Hope .f.114/222 X Roberts 277/59 X Willcox 114/222 Primary Examiner- MorrisKaplan Attorney-Davis, Hoxie, Faithfull & Hapgood 57 ABSTRACT A methodof applying a protective coating to a surface under water whichcomprises forcing a protective coating composition through an applicatorpad, for example using compreseed air, at a pressure at least equal tothe ambient pressure of the water at the depth at which the coating isapplied, and applying the coating composition to the surface by asmearing action of the pad. Apparatus for carrying out the methodincludes a porous applicator pad, a reservoir for a protective coatingcomposition to be supplied to the applicator pad, a sensing device forsensing the ambient water pressure, and a control device operative tomaintain the pressure at which the composition is supplied to theapplicator pad at least equal to the sensed pressure. The applicator padmay be a layer of foamed "plastics material having an openinterconnected cellular structure.

9 Claims, 3 Drawing Figures maintenance of marine vessels. In the caseof yachts and smaller vessels, it is necessary to haul the vessel out ofthe water in order to apply paint to the surface of the vessel which isnormally under water. In the case of larger vessels, the ship must beplaced in a dry dock in order to carry out painting of the lower partsof the hull. In both cases, substantial time and expense are involved inputting the vessel into a condition where the paint can be applied usingnormal methods. In the case of merchant vessels, the time involved inwaiting for a dry dock to be vacant and putting the vessel into the dockis frequently a substantial proportion of the time actually involved inpreparing and painting the hull. This, of course, represents asubstantial amount of lost revenue while the vessel is out ofcommission. Nowadays, with larger and larger merchant vessels beingbuilt, there are fewer dry docks available for the very large vesselsand maintenance of the lower parts of the hulls under water becomes anincreasingly intractable problem. i r

Paints are, however, available which are capable of setting to form anadherent coatinglunder water butdifficulty has been experienced indevising a satisfactory method of applying such paints to surfaces underwater.

According, there isprovided a method of applying paint to a surfaceunder water which comprises forcing paint to an applicator pad at apressure'at least equal to the ambient pressure of the water at thedepth at which thepaint is applied, and applying the paint tothe FIG. 3is a sectional side view of the applicator shown in FIG. 2.

Theapparatus shown in FIG. 1 comprises an applicator 1 connected by aconduit 2 to a paint reservoir 3. The paint reservoir 3 may be locatedon a quay or diving tender, but where the apparatus is portable, it isconveniently carried on the back of a diver. Paint is forced from thereservoir 3 to the applicator by means of compressed air which is fedalong a conduit 4 from a control unit 5. The control unit 5 is connectedto a source of compressed air (not shown) by means of a conduit 6 havinga suitable self-sealing adaptor 7. The pressure in the compressed airconduit 4 is monitored by means of a gauge 8 which is connected toconduit 4 by means of an air line 9. The gauge 8 is conveniently worn onthe divers wrist. It will be appreciated that each of the conduits 2, 4,6 and 9 are constructed from a flexible material such as rubber or athermoplastics material. The air supply system also includes apressbutton operated bleed valve 10 which can be operated .by the diverin order to releasepressure from the system and thus to stop the flow'ofpaint to the applicator.

. Pressure in the system can be increased by operating a control valve11 in the control unit 5. The effect of this is to increase the airpressure fed to the reservoir 3 and thus to increase the flow of paintto the applicator 1.

FIGS. 2 and 3 show the construction of the applicator l in more detail.As will be seen, the applicator cornprises a housing member or body 20formed from a corrosion resistant metal which is provided with a mainlongitudinal passage 21 for feeding paint to its lower surface. Atransverse passage 22 extends from a side wall of the body 20 andcommunicates with the end of the passage 21 remote from the lowersurface of the body 20., The passage 22 is appropriately sized toreceive the constrictedend of a stainless steel tube 23 which is formedwith an aperture 23a which coincides with the upper end of the passage21. The tube 23 is clamped into the body-20 by means of two bolts 24 andsealed intothe body by means of an epoxy resin glue.

. Thetube 23 is conveniently provided with a handle 25 surface by asmearing action of the padi'Normally; the

paint is; forced to the applicator by means of compressed-air; l I n Theinvention provides apparatus for carrying out the method which includesaporous applicatorpad, a reservoir-for paint to be supplied to theapplicator pad, a

sensing device for sensing the ambient water pressure,

and a control device operative to maintain the pressure at which thepaintissupplied to the applicator pad at least equal to the sensedpressure.

I Preferably, theporous pad is of flexible foamed plas-,

tics material having an open interconnected cellular structure. Examplesof suitable foam jplastics materials are polyether, polyester andpolyurethane foams having open interconnected cellular structures. Ithas been (see FIG. 1) and atits free end with a pipeunion26 forconnection to the rest of'the ap'paratus'As shown in FIG. 3, the lowerface of the ll$ody20 is convexly curved and a layer 27'of flexiblefoamed plastics material having an open interconnected cellularstructure is held in contact with the lower face of the body 20.Desirably, this foam layer is about 5 cms. thick and itsflexibilityenables it to conform torthe shapeof the surface beingpainted and to exclude water from the interface. A ring 28 of brassorother corrosion resistant metal serves to clamp'the pad comprising thefoamed plastics layer 27,an'd a towelling outer cover 29 into foundadvantageous in practice to cover the free face of the plastics foamwith a porous fabric and a particularly useful fabric has beenfoundto bea pile fabric contact with theib'ody Snap fasteners 30 (shown hold thering 28 to the body 20.

only in FIGS. 1 and 2) aregconveniently provided to It vwill beappreciated that the body 20 of the applicator, the tube 23 and the ring28 may alternatively be manufactured from aplastics material, forexample nylon, and in this case the tube 23 may be moulded inte grallywith the body during manufacture.

In the use of the apparatus, air is fed along conduits 6 to the controlunit 5 which includes means for sensing the ambient pressure at whichthe apparatus is used and is arranged to supply air along the conduit 4at a pressure which is at least equal to the ambient pressure.

This ensures that water is not forced backwardly through the applicatorpad into the apparatus. When the diver wishes to vary the rate at whichpaint is fed to the applicator pad, he operates the valve 11 to increaseor decrease the rate of supply of compressed air and applies the paintby moving the applicator 1 across the surface to be painted using asmearing action. If the diver wishes to stop the flow of paint to theapplicator this can be done by turning the control valve 11 back andpressing the operating button of the bleed valve 10. The control unit 5,however, ensures that the pressure does not drop below the prevailingambient pressure, 7

because although the air supply is cut off, the pressure within thepaint reservoir cannot fall below the external pressure at the pad,unless of course the apparatus is taken to a greater depth.

It is found that using the apparatus in accordance with the invention,it is possible to apply an anti-fouling paint to a thickness of 0.05 mm.in one pass of the applicator. Since there are no cocks, valves or othermoving parts in contact with the paint the possibility of clogging iseliminated and cleaning and maintenance are facilitated. When aparticular painting operation has been completed and the apparatusreturned to the surface, the paint line can be cleaned by simply replacing the reservoir 3 with a receptacle filled with a suitable paintsolvent. By blowing the solvent through the conduit 2 and the applicator1, the apparatus is effectively and conveniently cleaned.

The applicator 1 can be manipulated by hand, and the one illustrated isdesigned for such use. However, the applicator may also be manipulatedby mechanical means. For example, an applicator may be mounted on anunderwater vehicle and be driven so that it performs an orbital movementin contact with the surface to be painted. In a further development ofthe apparatus, the applicator may be arranged to travel on a magnetictrack along the ships bottom or other steel surface and the operatorcansimply follow the applicator and control its direction and the flowof paint to the applicator 4 pad.

What is claimed is:

1. Apparatus for applying paint to a surface under water comprising aporous applicator pad, a reservoir for paint, means for supplying paintunder pressure from said reservoir to said pad, sensing means forsensing the ambient water pressure adjacent said pad and control meansresponsive to said pressure sensing means for regulating the pressure atwhich paint is supplied from said reservoir to said pad.

2. Apparatus according to claim 1, in which the applicator pad is alayer of foamed plastics material having an open interconnected cellularstructure.

3. Apparatus according to claim 2, in which the free face of the layerof foamed plastics material is covered with a porous fabric. i

4. Apparatus according to claim 3, in which the fabric is towelling.-

5. Apparatus according to claim 1, in which the pad is held between aretaining ring and a housing member, said housing member having apassage or passages for supplying the paint to the pad.

6. Apparatus according to claim 5, in which the housing member isconnected to the reservoir, and the reservoir is connected by a supplyline to a source of compressed air for forcing paint from the reservoirot the applicator.

7. Apparatus according to claim 6, in which a pressure regulator isdisposed in the supply line whereby the pressure in the apparatus andhence the rate of feed of the paint can be controlled.

8. Apparatus according to claim 6, in which the supply line includes anormally-closed bleed valve which is adapted on operation to releasecompressed air from the supply line and thus to reduce the pressure inthe supply line.

9. Apparatus according to claim 8, in which a pressure gauge isconnected into the supply line.

1. Apparatus for applying paint to a surface under water comprising aporous applicator pad, a reservoir for paint, means for supplying paintunder pressure from said reservoir to said pad, sensing means forsensing the ambient water pressure adjacent said pad and control meansresponsive to said pressure sensing means for regulating the pressure atwhich paint is supplied from said reservoir to said pad.
 2. Apparatusaccording to claim 1, in which the applicator pad is a layer of foamedplastics material having an open interconnected cellular structure. 3.Apparatus according to claim 2, in which the free face of the layer offoamed plastics material is covered with a porous fabric.
 4. Apparatusaccording to claim 3, in which the fabric is towelling.
 5. Apparatusaccording to claim 1, in which the pad is held between a retaining ringand a housing member, said housing member having a passage or passagesfor supplying the paint to the pad.
 6. Apparatus according to claim 5,in which the housing member is connected to the reservoir, and thereservoir is connected by a supply line to a source of compressed airfor forcing paint from the reservoir to the applicator.
 7. Apparatusaccording to claim 6, in which a pressure regulator is disposed in thesupply line whereby the pressure in the apparatus and henCe the rate offeed of the paint can be controlled.
 8. Apparatus according to claim 6,in which the supply line includes a normally-closed bleed valve which isadapted on operation to release compressed air from the supply line andthus to reduce the pressure in the supply line.
 9. Apparatus accordingto claim 8, in which a pressure gauge is connected into the supply line.